At first glance, the difference doesn't look that big, but notice the values of the axes. The axis for men on the horizontal is from 0 to 200, the axis for women is 0 to 20, and the equal ratio line is the purple one that's nearly vertical. So the only article with more women contributors is on cloth menstrual pads.

This is totally fascinating to me – certainly both men and women use Wikipedia, why is it the vast majority of editors are men? Is this imbalance reflected to some degree in general usage? Or donation?

Why? Well, why is it the vast majority of programmers or coders men? And therein you have part of the answer to your question! Go to any page and click ‘edit’ – it is a hugely discouraging feeling, if you don’t know how to program or if you’re not previously familiar with mark-up text (http://en.wikipedia.org/wiki/Help:Editing).

Wiki markup is great, but it not accessible to most users. And the current support with regards to text editors is not much better (http://en.wikipedia.org/wiki/Wikipedia:Text_editor_support). In my opinion it is a huge loss for wikipedia and its community, since i think that there are many people out there (perhaps especially women), who would like to contribute but can’t.